Composition of matter comprising a polycarbonamide and cured rubber fines



United States Patent 3,491,034 COMPOSITION OF MATTER COMPRISING A POLY- CARBONAMIDE AND CURED RUBBER FINES Russell L. Seelig, Springfield, Mass., and John M.

Mersereau, Cheshire, and Paul J. Mester, Stam- Patented Jan. 20, 1970 ICC Similarly, the vulcanized rubber fines used in forming the instant composition of matter may contain the usual compounding ingredients and fillers as these do not interfere with the utility of the composition. Such fines may consist primarily of one or more hydrocarbon rubbers,

ford, Conn assignors to Uniroyal, Inc. New 5 such as natural rubber, styrene-butadiene copolymer rub- York, N.Y., a corporation of New Jersey l/ rubber, ethylenbpropylene copolymer rubber, No Drawing. Filed Oct. 30, 1967, Ser. No. 679,159 P y ene rubber, cis-polybutadime rubber, cis-poly- Int. Cl. C08g 41/04 isoprene rubber and other rubbers conventionally used in U.S. Cl. 2603 5 Claims tire manufacturing. For economical preparation vulcan- 10 -ize d hscrap tires may be used to prepare the rubber fines.

e sizes of the vulcanized rubber fines useful in the ABSTRACT OF TH DISCLOSURE instant invention will vary, but preferably the fines are A mixture of nylon with a small amount of vulcanized Smaller than The opfinings of approximately a 100 mesh rubber fines which improves upon the physical properties Standard Sieve Size Screen Sieve Openings being f di l about 0.0059 inch in the shortest distance across).

The novel composition is simply formed by adding from 0.001 to 0.5 part of the vulcanized rubber fines to The present invention relates to a novel composition correspondlllg 99.999 to 99.5 parts by weight of the of matter suitable for use as a molding composition. 2 9 and 9 9 the two m a Plastlc extruder Nylon is the generic name for the synthetic linear polyl other slmllarly q q Processes for P amides and includes, by Way of example such polymers ducmg a homogeneou s particle d1spers1on. The resultant as polywexamethylene adipamide) commonly known as composltlon 1s a practlcal molding composition, generally nylon 66 polycaprolactam known as nylon 6 poly(hexa s1m1 lar t-o nylon, but super1or thereto 1n tensile modulus, methylene sebacamide) known as nylon 610, and poly(:- tensne strength and tenslle Impactamino-undecanoic acid) known as nylon 11, etc. The EXAMPLE 1 nylon polymers are' used for many varied applications, a few examples of which are mono-filament fishing yarns, Vulcanized rubber fines were obtained by grinding fabric for wearing apparel, and plying with rubber in vulcanized tire scrap (consisting of a major proportion tires, gears, pipe fittings, wire covering and the like. of styrene-butadiene copolymer rubber and a minor pro- A prime disadvantage of nylon is its low modulus of portion of natural rubber, as well as the customary elasticity relative to other rigid plastic polymers. The amounts of carbon black and other commonly used rubtensile strength and tensile impact of the nylon polymers ber additives) obtained from a standard passenger tire are also often lower than desired. and passing the fines through a 6 mesh U.S. Standard It is an object of this invention to provide a new com- 5 Sieve Size screen, the sieve openings being about 0.130 position of matter having the desirable properties of inch in the short-screened through a 100 mesh screen (the nylon, but displaying a higher modulus of elasticity than sieve openings being about 0.0059 inch across). The 100 pure nylon. mesh vulcanized rubber fines were then mixed at 550 F. It is a further object of this invention to provide a with nylon 66 (technically called poly(hexamethylene practical molding composition generally similar to nylon, 40 adipamide)) in a screw-type thermoplastic extruder, the but superior thereto in tensile modulus, tensile strength relative weight quantities of each being shown in Table 1. and tensile impact. The mix was then cooled, granuIated and injection mold- Briefly speaking, the present invention concerns a novel ed into standard ASTM (American Society for Testing composition of matter comprising from about 0.001 to and Materials) test specimens suitable for measuring about 0.5 part of vulcanized rubber fines and a corre physical properties. The test specimens were next suitably spending 99.999 to 99.5 parts by weight of nylon. More conditioned to assume a uniform moisture content by particularly, the present invention concerns a novel moldbeing allowed to come into equilibrium with a rela ing composition comprising a homogeneous dispersion of tive humidity at 73 F. (about a 2% water content). The said vulcanized rubber fines and said nylon. conditioned specimens were then tested for the physical The nylon used in forming the instant composition of 50 properties noted in Table 1.

TABLE 1 A B C D E F G H Wt. percent nylon 100.000 99.999 99.990 99.900 99.800 99.500 99.000 98.000 Wt. percent vulcanized rubber fines (100 mesh) 0.000 0. 001 0.010 0.100 0.200 0. 500 1.000 2.000 Tensile strength (ASTM D412),p.s.i 7,100 7, 400 7,560 7,790 7,710 7,020 7, 030 Tensile modulus (ASTM-D-412), p.s.l. X

10- 1.2 1.3 1.3 1.3 1.4 1.0 1.2 1.2 Tensile impact (ASTM D-1822 61T, using atypeLbar),tt.-lbs.lin. 175 210 198 231 203 210 149 131 matter is preferably one or more of the aforementioned polymers or heteropolymers of any of the monomers used to form any of the above-mentioned nylon polymers. The purity of the nylon used in forming the instant composition of matter is not critical as the improvement in physical properties resulting from the addition of vulcanized rubber fines will not be affected by the presence of other chemicals. However, the presence of low molecular weight materials, such as antioxidants should be limited to less than 2%. Thus even reclaimed nylon tire cord may be used in the present composition.

The increased tensile strength, tensile modulus and tensile impact demonstrated for compositions having a 0.001 to 0.5 wt. percent level of fines enable molded parts to be produced which are more rigid and tougher than molded parts of comparable size made out of pure nylon. Alternatively, the improved physical properties of this new composition of matter may be utilized to produce a molded part comparable to a molded part of pure nylon in rigidity and strength, yet considerably reduced in thickness or cross-section.

It will be noted from the data of Table 1 that the tensile modulus and tensile impact advantages obtained by adding to the nylon small amounts of fines (0.001% and up, based on their combined weights) are lost somewhere above the 0.5 wt. percent level of fines. Although even at the 2% level of fines there is an improved tensile strength, the various compositions having a greater than 0.5 Wt. percent level of fines demonstrate such serious surface imperfections (relative to pure nylon) as to obviate consideration thereof for use as practical molding compositions.

Many modifications and uses of this composition will now become apparent to those skilled in the art. Consequently, the spirit and scope of this invention should not be considered as defined by the foregoing disclosure or the desired embodiments with their specific percentages and compositions, but by the appended claims.

Having thus described our invention, what We claim and desire to protect by Letters Patent is:

1. A novel composition of matter comprising from 0.001 to about 0.5 part of vulcanized rubber fines having a diameter smaller than .0059 inch and a corresponding 99.999 to 99.5 parts by weight of a polycarbonamide having repeating carbonamide groups as an integral part of the polymer chain.

2. The composition of claim 1 wherein said vulcanized rubber fines are comprised of one or more of the rubbers selected from the group consisting of natural rubber, styrene-butadiene copolymer rubber, butyl rubber, ethylene-propylene copolymer rubber, polybutadiene rubber, cis-polybutadiene rubber and cis-polyisoprene rubber.

3. The composition of claim 1 wherein said polycarbonamide is selected from a group consisting of polycaprolactam, poly(hexamethylene adipamide), poly(hexamethylene sebacamide), poly(aminoundecanoic acid).

4. The composition of claim 1 wherein said vulcanized rubber fines are prepared from vulcanized scrap tires.

5. The composition of claim 1 wherein said polycarbonamide is reclaimed tire cord.

References Cited UNITED STATES PATENTS 2,249,686 7/1941 Dykstra 260-857 2,809,944 10/1957 Sverdrup 260-2.3 2,853,742 9/1958 Dasher 2602.3

SAMUEL H. BLECH, Primary Examiner M. I. TULLY, Assistant Examiner U.S. Cl. X.R. 260-23, 857 

